While I in no way condone censorship or dictatorship I can remember a few pieces.
Triumph of the Will is still looked at as a millstone in cinema, and the soviets produced very memorable sculptural works such as The Motherland Calls to name two. Both regimes also had some of the most memorable (propoganda) posters ever made, that are still awesome visual works to this day (even though the content they communicate is abominable).
Point taken, the Nazis had hilariously bad taste in art. But what about Pasternak, Solzhenitsyn, and the rest of the great Soviet dissident literary canon?
Just look at Biedermeier, Nazi or Soviet era art to get a comparison what wide-spread censorship and surveillance can do to a society.
What's that? You don't remember any because it's either boring as fuck or blatant propaganda?
Oh, hm. Well.
(Okay, it's not that bad in reality. But periods of mass surveillance usually weren't golden ages of creativity, to put it mildly.)